What is GPS?

GPS (Global Positioning System) is a satellite based network which consists of 24 satellites orbiting Earth. These satellites have been placed by the U.S. Department of Defense and just like the internet, GPS was originally intended for military use, but was made available to civilians. These satellites orbit the Earth twice a day and transmit signals to Earth. GPS data is used as navigation aid for planes, ships and cars and is commonly bundled into PDA’s, phones and computers. The GPS system is divided into 3 components – space, control and user.
The 'Space segment' consists of the satellites orbiting Earth about 12,000 miles above us. They travel at speeds of about 7000 miles per hour.
The 'Control segment' consists of the tracking stations all over the world. These stations measure and compute signals from the satellites.
The 'User segment' consists of the GPS receivers and users.
To learn more about GPS, click on the links below

Global Positioning System

Global Positioning System Overview

How GPS Receivers Work